Ha! My brother dated a divorced woman from England for a while after his divorce (she was hilarious). She told a story of when her and her American husband first moved to the US.In the UK, I understand that it is very common to say "I'll ring you up" when we say "I'll call" and our "I'll drop by" to the Brits is "I'll knock you up".
They had a milk delivery every morning, and she asked the milkman if he would "knock her up" (meaning wake her up) when he delivered the milk. The milkman replied, "Lady, I'll knock you up anytime."
After relating the story to her husband, he was the one that greeted the milkman the next morning...